The present invention is directed to an apparatus for measurement of a plurality of light waveguides, which apparatus comprises an optical transmitter that can be coupled via a coupling device into the light waveguides to be respectively measured, as well as has an optical receiver which provides a signal to an evaluation means.
A measuring instrument for measuring a plurality of light waveguides is disclosed in U.S. Pat. No. 5,090,802, whose disclosure is incorporated herein by reference thereto and which claims priority from the same British Application as Published European Application 0 411 956 A2. In this patent, the measuring instrument includes an optical switch via whose transmission channels respectively one of two light sources having different wavelengths can be individually coupled at their end faces into a plurality of light waveguides in chronological succession. The light waveguides are, thus, respectively, permanently spliced to the transmission channels of the optical switch. For evaluating a multi-fiber junction in the course of the path of these light waveguides, an optical receiver having a reception element, which is preferably a large-area detector for all light waveguides to be measured, is provided at the reception side. A test signal is, respectively, individually and sequentially supplied into the light waveguide connected to the transmission channels of the optical switch at the transmission side and is picked up at the reception side with the reception element and is separately evaluated. A variable, separable coupling or, respectively, uncoupling of the light waveguides is relatively difficult to accomplish, since the light waveguides to be measured are spliced, i.e., permanently connected to the transmission channels of the optical switch.
A separation of the spliced connections already existing would be respectively required, first for coupling new light waveguides to be measured. The light waveguides would then have to respectively have their end or open end face spliced to the output of the optical switch. This known measuring instrument could, thus, hardly be used for a flexible, destruction-free coupling or, respectively, uncoupling of the respective light sources as desired, for example, in optical transmission links having light waveguide ribbons for checking multiple spliced connections.
U.S. Pat. No. 5,040,66, whose disclosure is incorporated herein by reference thereto and which claims priority from German Application P 34 29 947, discloses a measuring instrument for evaluating a splice of an individual light waveguide. The transmission signal is supplied into the light waveguide before the splice with the assistance of a flexural coupler and is coupled out at the reception side following the splice with a second flexural coupler. The exit field of the outfed transmission signal is received by a photodiode and is subsequently displayed. If one were to place a plurality of light waveguides into this known measuring instrument, then it would, at most, be the simple sum of the individual, infed radiation fields of the light waveguides that could be measured. The statements and conclusions about individual optical transmission characteristics of the individual light waveguides derive from this superposition sum are not possible within the known measuring instrument, since a functional dependency between the individual, optical measured values cannot be derived from this sum.